Let-off mechanism for looms



0a. 13, 1931. H. A. DAVlS ,8 7,712

LET-OFF MECHANISM FOR LOOMS w Filed Dec. '31, 1929 2 Sheets-Shut l m V I a-ri filllllllll HHIIHHIHHIIIIlllllllll-Hlllll IIIIU lllll Oct 13, 1931. DAV|5 1,827,712

LET-QFF MECHANISM FOR L OOMS .Filed Dec. 31, 1929 2 Sheets-Sheet 2 Fig.

lnvenTor. Harry A. Davis byw ATTys,

Iessary v to illustrateland. describe in detail Patented Oct. 13, 1931 @ESTATES LP-ATEN'T so FFII'CE nanny a; DAVIS,"'OF HOPEDALE; massacnusnrrs. AssreNoa T DRAPER CORPORA- TION;"OF HQPEDALE, massacnusmrs, A CORPORATION or MAINE LET-OFF. MECHANISM FOR 'LOOMS 1;. Application filed December 31,1929. Serial-No. 417,689.

7 Thisv invention relates toa let-o fi' mecha- ..-nism,for a. loomihaving two warp beams, as i inthecase ofabroad or wide loom where the WarpQis divided-between two:beams arranged 5. in axial alignment.

Heretoforelletsoif mechanisms have been iprovidedlfor this ,type of-loom in which the let-offmechanismhas acted through differen- ...Itia1ldrivinguconnectionsbetween it and the. .10 two. warpbeams'thusautomatically to equalize the tension on the warps on both beams iandithroughoutthe entire warp sheet. Such .a im'e'chanism of. a. highly improved type is fshownflinmy. Patent No. 1,749,131, granted order to utilize to full advantage the benefits Of the differential drive. the component parts "the two warp beams.

Theobject'of the invention is to provide means which shall act to oppose any tendency "of one beam to bedrivenffaster than the other. V

The nature and objects of the invention will: appear more fully from the accompanyingflilescription and, drawings, and will be .thoseparts of such armechanism with which fftheiinventionfis directly concerned. a The wdrawings forthis, purpose illustrate a mech-,

anism such as shown in my aforesaid Patent ...N0..;1,749,131. a v

. In .thedrawings: 1

. Fig. 1 is avview partiallybroken away and =;--:pa1'tial1y.-invertical section looking from the :fnont iofitherloom toward. the warp abeams, itheirrsupport, and the let-'oif mechanism.

2; I Fig. 2 is "anend view-ofoneof the warp -Eig'i 3-is adog' for securing one of the 'warp Fig. 4is a side elevation of a clamping bolt 1 for thedog. I

In the construction illustrated, the side frames 1 and 2 of the loom and an intermediate support 3 are each provided with aligned journal bearings in which is supported the beam supportingv shaft 4. The twowarp beams 5 and 6 are journalled on the shaft 4: and are shown as of .thevusual' form having the heads 7. The outer head of-each' warp beam has secured or formed thereon the large gear 8 and preferably also thc'drum 9 to receive the usual friction band.

The let-off mechanism is shown vas of the type of the well:knownDraper-Roperlet- .of' mechanism disclosedin Patent No. 647,815,

granted April 17, 1900, and in my aforesaid patent. Asthis mechanism is not specifically concerned with the present, invention, it is unnecessary to describe itin. detail. It is .suflicient to .note that thismechanismacts positively to rotate theinternal gear 10 journalled on, the shaft 11 which extends transversely ofthe loom. This gear haskeyed thereto a clutch element12 bymeans of which it maybe connected toor'disconnected from #t-he ,difieren'tial drive.

This mechanism is shown as comprising a rotary element 13 driven by the gear 10 and journalled on the shaft 11. This 'elementhas journalled theretolon axes extendingradially of the shaft 11 one or more pinions 14 herein shown as two in number. These p1I1lO.I1 S mesh wlth apair of gears 15 and 16. The gear 15 is keyed to the shaft 11 and the shaft- 11 has secured thereto a pinthe right-hand beam 6, viewing 1. The gear 16 forms part of or 1s secured to a sleeve the gear 8 of the left-hand warp beam 5, viewing Fig. 1. It is to be understood, however, that any suitable means may .be employed other than the well known Draper- Roper let-off to drive the element 13 of the differential mechanism.

' If a greater resistance is met in driving the shaft 11 than that encountered in driving the sleeve 18, there is a resulting tendency for the latter to be driven faster than the former as ion 17,.sh0wn as meshing with the gear 8 of when let off occurs thus causing an unequal tension throughout the warp sheet. In the design of a loom of this type it is practically impossible to build a differential drive in which the frictional resistance of the elements driving one of the beams will be equalto the frictional resistance of the elements driving the other beam. Consequently, the beam driven by the elements having the least fricwhen let off takes place.

The difference. in the degree of friction? existing in the train of mechanism driving the two beams may be 'ill'ustrat'edin the embodiment herein shown by pointing out the relatively greater number of bearings in which the shaft 11 .turns as compared to the bearingsof the sleeve 18. Within the. let-0E mechanism itself the rotation of the shaft 11 is resisted by the" friction of the bearings 30,

31, 32 and 33. The relatively great length of the shaft necessitates the use of two intermediate supportingbearings 34 and while its extreme end must be supported in the -bearing'36 on the loom side 2. On the other "hand, thesleeve 18 carrying the beams 16 normal conditions it consumes more power to drive .the' shaft 11 than the sleeve 18 which resultsin an inequality of drive to'the two beamsy t It is' the purpose of the present lnvent on to provide. means to opposethis tendency of 1 one'beam' to'be driven in advance ofthe may be found, however, when the machine 7 is assembled that the tendency will be to drive the beam 6 faster than the beam 5. For structural reasons it is difficult to re" duce'the friction on the shaft 11 which drives the beam 6. It is, however, practical to introduce friction in the drive of the beam 5,

and in'this manner equalize or offset an excessive variance in the resistance offered by excessive, resistance should appear in the 5, means must be provided to offset this undesirable resistance by adding resistance to Specifically this result is secured by looking either one or-the other of the beams to .the shaft 4. 'The device shown as provided forthis purpose is a dog '20 fitting the shaft 4 and adjustable longitudinally thereof and provided with means by which itamay be clamped to the-shaft in any desirable posii tion of longitudinal adjustment. Suchmeans is shown as. a screw 21 fitting a transverse bore 22 inthe dog and'having a cut awa tion is driven faster than the other ibeann idog to the beam or the beam to the shaft.

;of bearing points in which it must turn. It

the shaft 11. If, as above pointed out, the? the train of mechanism driving the beam 6.-

-- 1 h g y the shaft thus to cause .t d e portion 23 to fit over the shaft 4. This; bolt a en ency s'ald is shown as provided with a groove 26 adapted to fit over a radial rib 27 on thefbeam thus rendering the dogconnectible and disconnectible from the beam, but any suitable -means may be provided for connecting the in fact, for connecting The function of the dog 20 and its application to the principle of the invention is as follows. "It'is" assumed invthe specific inbearing3 in whichfthe shaftmust now ro- 'tate., P

and'19 rotates on the shaft 11 at two bearings only, namely 32 and33. Obviously, under:

A positive resistance isthus introduced in a very simple and effective manner to offset the excessive dragon the shaft 11 and cause 4 the two beams to be driven evenly and differentially.; j a J Without going. further into detail, it will be seen that when the gear 10 is" clutched to the; element 13 and thelet-oif mechanism is acting positively to rotate the gear 10, the two beams will be'driven forward through the differential mechanismjso as toequalize the tension throughout the .warp sheet. Having thus described the invention, what is claimed as new and desired to be secured 1105 by Letters Patent, is:

1. A-let-off mechanism for a loomhaving twowarp beams comprising a positivelyrotated let-off member, a shaft journalled in. the loom' frame and having; both warp beams" ournalled thereon,fdiiferential driving connect ons between the' let-off member and both warp beamswhereby the tension on the warp on both beams is continuously equalized and s V y 7 means actin to oppose any tendenc *of one tram of-mechanism which drives the beam 6 y beam to be driven faster thanthe other due to unequal resistance oflered to said driven let-off member by said differential driving connections. L 2. A let-ofl mechanism for a loom having two warp beams comprising a positively rotated let-off member, a shaft journalled in the loom frame and having both warp beams ournalled thereon, differential driving com beam to be driven faster than the other to be opposed by the resistance set up by the additional power required to turn the normally non-rotating shaft.

3. A let-off mechanism for a loom having two Warp beams comprising a positively rotated let-off member, a shaft journalled in the loom frame and having both warp beams journalled thereon, differential driving connections between the let-off member and both warp beams whereby the tension on the warps on both beams is continuously equalized, and a dog secured to the shaft and engaging one of the warp beams to cause the said beam and the shaft to rotate together in either direction whereby any tendency of said beam to be driven faster than the other is opposed by the frictional resistance resulting from the drive established by said dog between said beam and the shaft.

4:. A let-off mechanism for a loom having the construction defined in claim 3, in which the dog is longitudinally adjustable on the shaft and is connectible and disconnectible with the warp beam by adjustment on the shaft toward and from the warp beam respectively 5. A let-off mechanism for a loom having two warp beams comprising a gear on each beam, a beam shaft journalled in the loom frame and having both warp beams journalled thereon, a driving shaft having a pinion meshing with the gear on one beam, a driving sleeve journalled on the driving shaft and having a pinion meshing with the gear on the other beam, a pair of gears secured one on the driving shaft and the other on the driving sleeve, a rotary driven element carrying a pinion meshing with said pair of gears and acting to drive them and consequently the two beams differentially to let off the warps on the two beams under a continuously equalized tension, and means connecting the beam driven the faster to the normally non-rotating shaft acting to oppose any tendency of said beam to be driven faster than the other.

'6.-A loom comprising let-ofi' mechanism, two warp beams journalled independently in axial alignment, differential driving connections between the let-off mechanism and both warp beams whereby the tension on the warps on both beams is continuously equalized, and means acting to oppose any tendency of one beam to be driven faster than the other by said driving connections.

In testimony whereof, I have signed my name to this specification',

HARRY A. DAVIS. 

